Thread: I have no running oil pressure

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I recently built a new motor for my chevy II. Its a 1973 block and I chaged it from a front sump pan to a rear sump with the new motor. That means that I had to put a new oil pump and pickup in it. I have oil pressure when i use a primer and an electric drill. But when i start it up there is no running oil pressure.

A couple of other things, I used the old oil pump driveshaft and everything else is new except the rods. Also I was sure that the oil pump driveshafts in SBC are all the same length. If anyone knows if the driveshaft for the pump in a 66 nova 327 is different cause the pump isn't the same.

Any ideas PLEASE!

Do you have any pictures of what you are using?

I dont have any pics of the driveshaft if thats what you mean

Pictures would help. But what you describe is also confusing.

When you say you have "pressure" when you prime it, do you mean you're getting a pressure reading on a gauge or you're seeing oil flowing from, say the rocker holes? What are you using to prime, a simple shaft, or a stripped distributor? And when running are you viewing the same pressure gauge?

Since you say it runs, we'd have to believe your distributor gear (which drives the pump shaft from the bottom of the dist via the gear on the camshaft) and cam gear are engaging properly. And since you've witnessed "pressure" that says the pump is pumping oil. So, once you fill in some blanks we can start looking at other things.

I am using a Matco master gauge and i have 60 psi When priming. I have used a striped distributor and also a priming tool.
The pressure gauge doesn't even move when running and the motor is starting to get tight. My digital camara was stollen so I can not take any pictures. I have a MSD distributor and box but have not hooked it up yet. Right now im using a HEI dis. that i got from the junk yard

Okay, then let's deal with your original thought of whether the intermediate shaft is too short since it sounds like you're not turning the pump with the distributor in there.

First things first, don't assume anything. Look in the end of the drive gear and make sure there's a drive tang in there to engage the shaft and that it's secure. Measure the length of the distributor from it's mounting flange (where the clamp holds it in place)to the bottom of the drive gear (the tang should be less than 1/8 " recessed). Take a straight edge across the distributor hole and measure down to the top of the pump shaft. The distributor should be 1/4" longer to get good egagement. If the length is good enough then make sure the distributor is seating fully. If it's not long enough, then you need a longer pump itermediate shaft.

I think Bob's diagnostic makes sense,,it wouldn't be the first time mix and match parts haven't lined up.Also,,,if you have the origional distributor,,it should be easy enough to compare the lengths with the new HEI one.
Measure it three times,,,,install once.

If the motor is already getting "tight" then you probably have already ruined the bearings. If you solve the oil problem you should replace the bearings or risk throwing a rod. Check the crankshaft too. it may need polishing.

Originally posted by The Al Show
If the motor is already getting "tight" then you probably have already ruined the bearings. If you solve the oil problem you should replace the bearings or risk throwing a rod. Check the crankshaft too. it may need polishing.

i dont even know if i would get it running first. tight is very bad. if you pull the pan you can see what the problem is and fix it before you run it.

Thanks for the imput guys. Just to let you know, I got a new oil pump shaft and its 1/4" longer than the origanal one. That should solve the pressure problem. Now I just have to pull the motor out and probably put new bearings in it.

I built a 350 once with a brand new high volume pump. I put in a 7qt pan. I started the engine, and no pressure. None, zip, nada. I went nuts.
I had to redo the crank and rods and I found the issue. The oil pickup was way too close to the pan bottom. I just put the parts in and turned the key. I never thought to check the pickup length with the pan.
Live and learn.
Two ways I learn, first is to rewrite the book, then pay for the right way. I am getting better.

I'm not real sure why you went to a rear sump pan to start with. I've always ran the stock front sump pan, pump, and pickup on my '67 327; and I've never had any oil related problems.

I'm curious if you are running headers, and if so, how do you get your oil filter on and off? The stock front sump pan has a recess specifically designed just for oil filter access, which is tight with stock manifolds and pipes. It really gets close with headers, especially Hookers. I always wind up forcing the filter between the pan and the header tubes, it never goes on or comes off easy. Seems to me like access would be impossible with a rear sump pan.

I'd agree with the others that you've probably wiped the bearings in your engine. When you don't see pressure at the guage withing 15 sec. or so after starting, SHUT IT DOWN, and don't turn it over again until you're sure your going to get oil to the bearings. A used engine can run a few minutes (I've heard of one going for 15 minutes+, but I wouldn't want to own it) without oil pressure without ruining it; but a newly built one doesn't have that luxury.

And finally, as for the intermediate pump shaft in a Chevy II V8 being a different length that other smallblocks; I don't think it is, but then again I've never laid it out beside another one, so it could be. I just don't have a definitive answer for that one.

Randy

I went to a rear sump because i put the mustang 2 bolt on front end on the car.

Originally posted by vurtok
[B A used engine can run a few minutes (I've heard of one going for 15 minutes+, but I wouldn't want to own it) without oil pressure without ruining it; but a newly built one doesn't have that luxury. [/B]

well, me and my buddy wanted to see how long we could run a maverick we were planning on putting a v8 in.... and ran the 200 for 120 miles with no oil at all before it finally siezed up and died